The remote-controlled connection of ducts is required, in particular when the ends to be connected are placed in zones which are difficult or impossible for access by man because of the risks encountered. This is particularly the case of underwater installations for producing oil in deep waters.
It is known that under such circumstances it is advantageous to dispose the equipments of such installations in independent modules which are connectable and which may be placed on the bottom and, where necessary, raised to the surface without requiring divers to be present at the bottom. It is then necessary to provide apparatus enabling firstly the establishment of connections between ducts to enable exploitation, and secondly enabling disconnections when it is necessary to raise one or other of the modules located at the bottom to the surface.
Thus, the applicants' French patent application No. 2,500,525 describes an exploitation module connection for modules such as wellhead modules, using ducts called gatherers by means of auxiliary modules. An auxiliary module may include, for example, valves for controlling the flow-rate of fluid, and in particular oil, through a gatherer, from or towards a wellhead module.
To this end, the auxiliary module likely to be raised or lowered in isolation includes a length of duct called a floating tube which serves to connect a wellhead module to a gatherer in order pass the above-mentioned fluids.
Naturally, the apparatus in accordance with the invention may be used without such a module and under different conditions of exploitation, in particular, it may be used without changing the main items which are mentioned in the present application, for example in installations which are dangerous to man because of the presence of intense radioactive radiation.
In order to facilitate understanding, reference is made in the following description to the connection conditions mentioned in French patent application No. 2,500,525, and in particular a connection is described between a duct having at least one end which is fixed or which is temporarily fixed to a gatherer whose end to be connected is located in a predetermined position prior to connection.
The duct and the gatherer have their respective end connectors aligned and facing each other and at a sufficient distance apart to enable an auxiliary module to be inserted therebeween, said auxiliary module carrying the floating tube with a complementary connector at each end thereof.
The gatherers terminate at determined positions on bases placed on the water bed, and the modules are placed in housings provided in the top portion of the bases.
Insofar as the modules are arranged to be positioned in their housings by remote-control from the surface and in particular where the auxiliary modules are arranged to be raised for replacement or for maintenance, it is necessary to leave room between each auxiliary module and the ends of the wellhead module and of the gatherer which it serves to interconnect in order to enable the auxiliary module to be displaced when it is disconnected from these two items.
Thus, during connection, it is necessary to displace the floating tube to connect one of its ends to the corresponding end of the gatherer which is then situated outside the auxiliary module and which is capable of a certain degree of movement. The floating tube is then displaced in the opposite direction pulling the gatherer with it so as to connect the other end of the floating tube to the corresponding end of the wellhead connection duct.
Preferably, the ends of the gatherer and of the connection duct are aligned, for example on a common horizontal axis to facilitate their interconnection by means of a floating tube.
In practice, it is difficult or impossible to correct offsets in level between the ends of the gatherer and the connection duct prior to their connection by the floating tube. Further, the meeting planes at the ends of the floating tube and the ends of the gatherer or the connection duct are not generally perfectly parallel as would be desirable for facilitating connection under remote control.
There is thus a grave risk of causing inacceptable deformation of the axis line of the internal channels in the assembly constituted by end-to-end connection of the gatherer, of the floating tube and of the wellhead connection duct after connection has taken place. This may be most inconvenient, in particular, when tools are required to pass inside the ducts and may jam at the deformations.